EP3209967A1

EP3209967A1 - Pyrotechnic drive device

Info

Publication number: EP3209967A1
Application number: EP15797837.0A
Authority: EP
Inventors: Peter Lell
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-10-22
Filing date: 2015-10-21
Publication date: 2017-08-30
Also published as: US20170314582A1; DE102014115397B4; JP2017535033A; DE102014115397A1; KR20170072902A; WO2016062304A1

Abstract

The invention relates to a pyrotechnic drive device with a housing (3), provided in which are a combustion chamber (5), with a pyrotechnic material (15) arranged in the combustion chamber (5), and an activation device (13) for activating the pyrotechnic material (15), wherein the combustion chamber (5) is bounded by a combustion chamber wall (3, 7, 13, 17, 33, 35), which is closed on all sides, at least in an initial state, and in one or more partial regions is respectively formed by a pressure-receiving area of a respective pressure-receiving element (17, 35), wherein, after activation of the pyrotechnic material (15), each pressure-receiving area of the pressure-receiving element (17, 35) receives a gas pressure generated as a result, in such a way that the pressure-receiving element (17, 35) moves and/or is deformed and/or a mechanical pulse is transferred by the pressure-receiving element (17, 35) to an element (19) to be driven that is mechanically connected to said pressure-receiving element, at least in the initial state, or to a substance (25) connected to said element to be driven. According to the invention, a remaining volume of the combustion chamber (5) in which no pyrotechnic material (15) is provided in the initial state is filled substantially completely with a liquid, gel-like or pasty filling material (21) and/or a soft rubber-like filling material (21).

Description

Pyrotechnic drive device

The invention relates to a pyrotechnic drive device having the features of the preamble of patent claim 1.

Pyrotechnic drive devices are used for a variety of purposes, for example, as drives for electrical switches, in particular disconnectors, as used in automotive technology to quickly and permanently disconnect the battery or the battery of a vehicle in case of danger from the electrical system of the car. Such a circuit breaker, which can also be referred to as a fuse, is described in WO 03/067621 A1. In one of the variants, a piston-like element is moved when a pyrotechnic material is triggered, whereby a safety gap, which exists between the movable element and a stationary element, is separated and thus the current path running over the safety gap is interrupted. Although in this document, the pyrotechnic drive of the piston-like element is still integrated into the electrical switch, however, such a drive can of course also be designed as an independent device.

Another application is in the medical field. Here it is particularly known to accelerate a dusty or powdery substance, for example a medicament, by means of a pyrotechnic drive in such a way that it can be injected directly into a tissue, ie without a carrier liquid, and without needles. In this case, the dust or powdery substance particles are shot directly into the tissue, in particular into the upper layers of the skin of a body, which is practically completely painless. Such a device is described for example in EP 1 599 242 B1. Here, in a variant by means of a pyrotechnic charge, a shock wave acts on a membrane, whereby a mechanical impulse is transmitted to the dust or powdery substance adhering to the membrane. The substance particles are thereby detached from the membrane and accelerated to a very high speed. In another variant, a piston is accelerated by a pyrotechnic propellant charge on with a correspondingly high speed the back of the membrane impinges and thus transmits a sufficiently high impulse across the membrane to the adhering material particles.

In known pyrotechnic drives, whether integrated in any device or as an independent device, the pyrotechnic material, which is provided for generating the pressure or the pressure surge (hereinafter also referred to as shock wave), introduced into a combustion chamber. The volume of the combustion chamber usually corresponds to the volume required by the pyrotechnic material. However, if only a small amount of the pyrotechnic material is needed, depending on the liveliness or burning rate of the pyrotechnic material, or if as little pyrotechnic material as possible should be contained in the assembly for reasons of maximum safety in the event of a fault, there is often the problem that the combustion chamber can not be made small enough, or that the pyrotechnic material, which is often in solid, for example, pressed form, can not be produced with the required tolerance to fill the entire combustion chamber. The residual volume of the combustion chamber, which is not claimed by the pyrotechnic material, and the air present therein or the gas present therein limits in particular the steepness of the pressure increase, which is generated after activation of the pyrotechnic material, additionally requires energy that the actual acceleration process the diaphragm or the piston is lost and also dampens the shock wave. Thus, the residual volume filled with air or a gas reduces the transmission of a fast mechanical impulse to the output element of the pyrotechnic drive device (also referred to below as an admission element).

It should be noted at this point that in the context of this description any deflagrating or detonatively converting (for example burning) material is referred to as a pyrotechnic material. This also includes feflagrierend implementing mixtures, such as Thermitmischungen or tetracene. A deflagration-converting material generates a pressure increase or a pressure wave whose propagation velocity is less than or equal to the speed of sound of the relevant medium. By contrast, a material that converts detonatively generates a pressure change, referred to as a pressure surge or shock wave, in the relevant medium whose speed is greater than the speed of sound in the medium.

This essentially results in two different types of pyrotechnic drive devices:

If a deflagration, i. used relatively slow-acting pyrotechnic material, so there is a relatively slow increase in pressure or a relatively slow pressure change or pressure wave in the millisecond range. If this relatively "slow" increase in pressure causes the respective loading element to undergo deformation or is moved, both effects on the loading element are also possible Acting as a piston formed Beaufschlagungselement be driven or designed as a deformable membrane Beaufschlagungselement is deformed relatively slowly, which leads to an increase in the volume of the combustion chamber and thus also to the desired acceleration of the membrane surface.

If a detonatively implementing pyrotechnic material is used, the generated pressure surge or the shock wave originating from it should in particular be utilized in order to produce the output power of the pyrotechnic drive device. The pressure surge (the shock wave) reaches the loading element or its loading surface before a possibly additional, much slower pressure increase in the combustion chamber volume can lead to its enlargement. The surge may be used to impart a mechanical power output via the biasing member to one or more driven members, for example, to particulate matter of a pharmaceutical agent adhering to a surface of the biasing member. The material particles are accelerated in this way in a very short time to a high speed and dissolve after reaching the maximum speed of the loading element. If these fast particles of material hit a technical surface, a tissue or a skin, they can penetrate to a certain depth due to their relatively high energy. The inventor has recognized that in both cases a combustion chamber volume which is not completely filled with the pyrotechnic material adversely affects the mechanical performance of the drive. In the case of using a deflagrating material, more pyrotechnic material is required than actually required (ie, without an unfilled residual volume of the combustion chamber). In the case of a detonatively converting material causes the unfilled residual volume of the combustion chamber, an attenuation of the shock wave through the material transition between the residual volume and the combustion chamber side surface of the loading element (loading surface) leads to a reflection of the shock wave and thus to a reduction of the drive power.

The invention is therefore an object of the invention to provide a pyrotechnic drive device which generates the highest possible and fast-acting drive power with as little pyrotechnic material.

The invention solves this problem with the features of patent claim 1.

The invention is based on the recognition that the negative influence of a residual volume of the combustion chamber, which may exist in the initial state of the pyrotechnic drive device (ie, prior to activation of the pyrotechnic material), can be reduced or completely avoided if the residual volume in the initial state of the pyrotechnic drive device (In particular, in the prevailing in the initial state in the combustion chamber pressure and the temperature prevailing therein) is substantially completely filled with a liquid, gelatinous or pasty filling material and / or a soft rubber-like filling material. By means of the filling material, a good coupling of the at least one impingement element to the energy released by the pyrotechnic material and the associated increase in pressure in the combustion chamber are achieved.

In the case of a detonatively reacting pyrotechnic material, the filling material should preferably be designed such that the shockwave generated by the activation of the pyrotechnic material, which has a higher propagation velocity than the speed of sound in the relevant material. has, as possible unattenuated and with the least possible reflection (in particular at the loading surface of the biasing element, which limits the combustion chamber) is transmitted through the filler material to the biasing element.

If, on the other hand, a deflagrating pyrotechnic material is used which generates a pressure wave which is slower than the speed of sound of the material in question, the filler material should preferably be designed or adapted to the deformation of the combustion chamber, in particular caused by displacement and / or deforming the at least one loading element, as well as possible and for the least possible energy is needed.

By filling the residual volume of the combustion chamber with a filling material is thus achieved when using a deflagrating pyrotechnic material that produced with the gas generated by the conversion process (hot gas in a reaction by burning pyrotechnic material) in the combustion chamber an immediate relatively steep pressure increase, with which the loading surface of the at least one Beaufschlagungselements is acted upon. Since no compressible gas is contained in the residual volume in the initial state of the drive device, no energy is required which would be required for the compression of such a gas volume and which could not be converted into a drive energy. In the case of using a detonatively converting material, a significantly lower attenuation or reflection of the shockwave is achieved during the transmission to the loading element.

Accordingly, the amount or the mass of the pyrotechnic material used can be significantly reduced compared to known embodiments in which a residual volume of the combustion chamber is filled with gas in the initial state. Tolerances in the production of the geometry of the combustion chamber and / or in the production of the pyrotechnic material, for example the geometry of a detonator, which consists of a Anzündeinrichtung with a pyrotechnic material attached thereto (this can be pressed into a solid and / or by a shell with this can be connected), by introducing the liquid, gel or pasty filling material and / or the rubbery filling material are compensated in the residual volume, without resulting from the disadvantages occurring in known pyrotechnic drive means, described above.

In the following, a liquid, gelatinous or pasty filling material is understood as meaning any material which, in an operating (ambient) temperature range in which the pyrotechnic drive device is to be used, and in the initial state thereby produced in the combustion chamber (in particular pressure and temperature) , gelatinous or pasty consistency. In particular, all natural and mineral oils should be included on a carbon basis, but also on a silicon basis. Examples of liquid filling materials are rapeseed and sunflower oil, but also transformer oil, mineral oil and the silicone oils available in various viscosities and the thickening agents which can be used here, such as silicon dioxide, highly dispersed silicic acid (HDK), glass beads, etc. Of course, different starting materials can also be mixed to form a filling material.

Such liquid, gelatinous or pasty filling materials can be materials with conventional Newtonian behavior. However, the non-Newtonian materials should also be expressly included. For example, it is possible to use materials with thixotropic behavior which, in the initial state of the pyrotechnic drive device, are no longer flowable, particularly under the action of gravity, but suddenly become significantly more fluid or flowable after the pressure increase has been applied. It is also possible to use so-called structurally viscous or pseudoplastic materials which, in the initial state of the pyrotechnic drive device, are no longer flowable, especially when exposed to the force of gravity, but suddenly become significantly more fluid or flowable when high shear rates occur. Common examples of such thixotropic or pseudoplastic materials are tomato ketchup, toothpaste, many fats or latex adhesive blends.

In the initial state of the pyrotechnic drive device, such substances may still have the desired properties, in particular the desired (high Re) Viscosity to prevent leakage of the filler material from the combustion chamber during assembly or storage of the device, while after activating the drive means of the higher pressure generated thereby in the combustion chamber for the function of the drive device advantageous properties, in particular then desired lower viscosity can be achieved.

The filler may also be a mixture of different materials. In particular, solid particles can be admixed with a liquid or gelatinous material. In this way, a pasty material can be produced whose flow behavior can be adjusted by admixing certain solid particles (for example talc, glass beads or fumed silicon, HDK). For example, admixing relatively large particles improves the flow behavior, while admixing many small particles usually makes the pasty material more viscous. The viscous property is advantageous in particular during storage. Such pasty filling materials often also have the above-described pseudoplastic property, because after the activation of the pyrotechnic material, the filling material is moved and breaks particle association from a certain shear rate, i. the cohesion between the particles and the liquid or gel material is lost.

According to one embodiment of the invention, the soft rubbery material may be a silicone-based or rubber-based material, which preferably has a hardness of less than or equal to 70 Shore A. This can ensure that the residual volume is substantially completely filled. A packing of such a material may be prefabricated and used together with the pyrotechnic material under pressure in the combustion chamber volume.

If the pyrotechnic material is designed to generate a shock wave, ie if a detonatively reacting material is used, then the filler material may be selected such that the shock impedance of the filler substantially matches the shock impedance of the one or more biasing elements only differ by a predetermined small amount thereof. This is an optimal coupling of the detonative implementation the shock wave generated by the pyrotechnic material reaches the at least one loading element. In particular, relevant reflections at the one or more application areas are avoided, that is, the reflection factor at the application area is substantially equal to zero or below a predetermined acceptable threshold.

The filler material should have low acoustic wave attenuation, especially when using a material that detonates, in order to achieve a low-loss transmission of the energy of the shock waves to the one or more impingement elements.

The filling material may be a fluid, in particular an oil. Depending on the desired properties, a synthetic or natural oil, for example a vegetable oil, especially sunflower oil may be used. Among the natural, vegetable oils, in combination with a detonative material, sunflower oil in particular has proved to be an outstanding filling material; synthetic oils are all made from low-viscosity silicone oils or silicone oleogels.

According to one embodiment of the invention, the filling material or a constituent thereof may be a fluid which completely or partially evaporates due to the energy released by the pyrotechnic material. As a result, the pressure increase or the pressure wave generation is amplified.

According to one embodiment of the invention, such a fluid or a component thereof may also have a boiling delay, wherein the component with bumping is preferably water. The bumping is due to the rapid heating of the fluid by the pyrotechnically generated energy above the boiling point, whereby a metastable state is reached, in which the fluid can evaporate explosively. As a result, the pressure wave generation is reinforced again.

As a positive side effect of a filled with a filling combustor so that the effect is greatly limited in the event of bursting of the combustion chamber, as for generating the desired pressures in the combustion chamber only one small fraction of the otherwise required pyrotechnic mass must be used and the fluid, unlike a gaseous medium, can hardly store energy that would be released when bursting the combustion chamber.

According to one embodiment of the invention, the biasing element may be a movable piston, the movement path may also be limited by provided in the housing stop means. In this embodiment, substantially the slower pressure increase in the combustion chamber is exploited to produce a mechanical output power. For a movable piston can hardly follow a shock wave with its usually larger mass and be moved at supersonic speed in the medium concerned. Limiting the travel of the piston prevents the piston from exiting the housing of the drive device. The generated hot gases thus remain in the combustion chamber and can not endanger the environment.

According to another embodiment, the Beaufschlagungselement may also be a membrane which is held stationary in the housing or which is held in a movable piston, the movement path is preferably limited by provided in the housing stop means. The membrane allows easy transmission of a shock wave generated by a detonatively translating material to one or more elements to be driven.

The membrane may have an output region, which is preferably a central region of the membrane, which in the initial state acts on an element to be accelerated, for example a plunger. In another embodiment, the output region in the initial state, a adhering to the membrane or connected to this accelerating and dissolving substance, for example, a solid, liquid or gel-like pharmaceutical substance wear.

According to one embodiment of the invention, the element or substance to be accelerated may be arranged completely outside the combustion chamber and a limiting element may be provided which provides an opening for the element to be accelerated or for the ejection of the membrane to be detached Stoffs and which limits the deformation path of the membrane in a region outside the output region.

According to another embodiment, the element to be accelerated can pass through the combustion chamber and protrude in the initial state at a position away from the membrane of the combustion chamber from the combustion chamber or the housing of the pyrotechnic drive device or terminate flush with it. Again, in turn, a limiting element may be provided which limits the deformation of the membrane, preferably in the entire region of the membrane, which undergoes a deformation when activating the pyrotechnic material.

As a material for the delimiting element are plastics, especially thermoplastics, such as polyoxymethylene (POM), as they are inexpensive to process, survive well after firing violent shocks against their geometry and without cracking and give the impact acting on them plastically yielding Strains in the membrane can be minimized.

A membrane may be formed as a multilayer membrane, preferably as a double-walled membrane having a first and second wall, which may be connected via an intermediate layer, for example, glued. This increases the safety against bursting of the membrane. This intermediate layer can also fulfill a sealing or sliding function.

In general, a fast movement with a small movement path can be coupled out of the drive device or a pulse can be transmitted to a driven element by means of a diaphragm, while a piston serves more to decouple a slower movement, usually with a larger movement path. A combination of both variants is also possible if the membrane is provided in a movable piston. The membrane can decouple a fast movement or a mechanical impulse (ie use the pressure surge or the shock wave) and the piston can use the virtually always present slower pressure generation in the combustion chamber for decoupling a slower movement or Simply increase the volume of the combustion chamber to reduce the pressure in the combustion chamber after the extraction of the fast movement. Thus, an excessive deformation of the membrane or even bursting of the membrane can be avoided, even if the piston movement is not used as such for driving purposes.

In Auführungsformen that use a detonatively implementing material, the housing of the combustion chamber or at least a part of the combustion chamber wall of a good heat conducting material, such as a good heat conducting metal such as copper or aluminum, consist. As a result, the rapidly spreading pressure surge is still well transferred to the loading element while the slowly building pressure, whose energy does not contribute to the drive power in these embodiments, is reduced, since the heat energy is absorbed by the housing or discharged through this to the environment. In the combustion chamber for this purpose, a filler piece of a corresponding material may be provided, which limits the combustion chamber (at least in part). Furthermore, at least a part of the combustion chamber wall can be formed by a filling piece which consists of a piece in the initial state of the pyrotechnic drive device, i. at the prevailing in the combustion chamber pressures and temperatures, solid material which is at least partially liquefied after the activation of the pyrotechnic material or converted into the gaseous state. As a result, the combustion chamber energy is removed, whereby the pressure in the combustion chamber is reduced.

Such a filler may in particular consist of dry ice and be designed to cover the entire combustion chamber or a part of the combustion chamber. Dry ice is easy to process and produces a relatively low pressure in the combustion chamber in the final state of the pyrotechnic drive device, whereby a pressure of between about 70 and 100 bar is established by the sublimation and the conversion back into the solid state. In certain embodiments, such relatively low and constant pressure over time is desired, for example, when a moving piston is used as the urging member to be held in an end position upon activation, or when the deformation of the diaphragm is to be maintained with a certain force , According to one embodiment of the invention, the membrane may have a the output range encompassing or provided within the output range, inwardly directed with respect to the combustion chamber preforming, which is designed for shock wave steering and / or for generating a cracking-frog effect.

Further embodiments of the invention will become apparent from the dependent claims.

The invention will be described below with reference to embodiments illustrated in the drawings. In the drawing show:

1 shows a schematic longitudinal section through a first embodiment of a pyrotechnic drive device with a membrane which acts on a driven portion with a driven portion, wherein Fig. 1 a the Ausgangszugstand the drive means and Fig. 1 b shows the state after activation of the pyrotechnic material and Representing completion of the drive motion;

Fig. 2 is a schematic longitudinal section through a second embodiment of a pyrotechnic drive device with a membrane carrying dust or powdery particles in a driven region, wherein Fig. 2a shows the Ausgangszugstand the drive device and Fig. 2b shows the state after activation of the pyrotechnic material and Completion of the drive movement and dispensing of the dust or powder particles represents;

3 shows a schematic longitudinal section through a third embodiment of a pyrotechnic drive device similar to the variant according to FIG. 1, wherein the combustion chamber volume is reduced by means of an insert part;

4 shows a schematic longitudinal section through a fourth embodiment of a pyrotechnic drive device with a displaceable piston which is connected to a pin-like output element, wherein FIG. 4a shows the output tensile state of the drive device and FIG. 4b shows the state according to FIG the activation of the pyrotechnic material and the completion of the drive movement represents; and

5 shows a schematic longitudinal section through a fifth embodiment of a pyrotechnic drive device similar to the variant in Figure 3 with a provided in the combustion chamber impulse transmission element, wherein Fig. 5a the Ausgangszugstand the drive device and Fig. 5b the state after activation of the pyrotechnic material and the Represents completion of the drive movement.

Fig. 1 shows a first embodiment of a pyrotechnic drive device 1, which is designed as an independent, functional device. Of course, such a device, as is the case with all other embodiments described below, in a higher-level device, such as a needleless, pyrotechnic injection device or an electrical limit switch, be integrated. In this case, one or more elements of the pyrotechnic drive device 1 integrated with corresponding elements of the parent device, in particular in one piece, be formed. The pyrotechnic drive device 1 comprises a housing 3, in which a combustion chamber 5 is provided. The combustion chamber 5 is bounded on a rear side by a bottom element 7, which has a receiving recess 9 arranged in a longitudinal axis A of the pyrotechnic drive device 1 and into which a pyrotechnic unit 11 with a foot region is inserted. The pyrotechnic unit 1 1 comprises an ignition device 13, which is connected to a pyrotechnic material 15. At least the pyrotechnic material 15 protrudes from the bottom element 7 into the combustion chamber 5.

The pyrotechnic material 15 may be a deflagrating or detonatively converting pyrotechnic substance, which is preferably formed into a body with a predetermined geometry or at least one opposite the other combustion chamber volume delimited, optionally flexible outer skin. For example, the pyrotechnic material 15 may be a pressed into a molding powder, which additionally surrounded with a flexible, such as rubber-like outer skin is. The outer skin can also serve to connect the pyrotechnic material 15 or the respective molded body with the ignition device 13.

The front end region of the combustion chamber 5 is delimited by a membrane 17, which is axially plastically and / or elastically deformable at least in a region which is centric with respect to the longitudinal axis A. The membrane 17 can, as in FIG. 1 a, in which the initial state of the pyrotechnic drive device 1 is shown before activation of the pyrotechnic unit 11, have a centric shape directed inwardly with respect to the combustion chamber 5, which is referred to as preforming, and can be generated by cold or hot deformation of an initially flat membrane depending on the material of the grain membrane 17. This preforming, which may comprise the output region of the membrane 17 or be provided within the output region, may help amplify the pulse to be transmitted or accelerated to an element 19 to be transmitted or to transfer energy when the pyrotechnic unit 11 is deactivated. The pre-embossing of the membrane 17 can initially counteract a deformation of the membrane at an incipient pressure increase within the combustion chamber 5 and then in the sense of a "crackpot frog" from the stable state, which is given in the initial state of the pyrotechnic drive device 1, in a further stable or unstable state However, this second state is of little relevance, since the membrane 17 is in any case deformed into an end state upon activation of the pyrotechnic unit 11. Such preforming of the membrane 17 can also be a deflection or focusing of the shock wave (FIG. The crackling effect or the focusing of the shockwave was able to detect by measurement an additional increase in the achievable surface velocity of the membrane in the output region of approximately 10 to 20 percent.

The residual volume of the combustion chamber 5, which is not claimed by the pyrotechnic material 15, or the ignition device 13, that is, the protruding into the combustion chamber portion of the pyrotechnic unit 11, is substantially completely filled with a filling material 21. The filler material may be liquid or gel-like. Also a soft rubbery filler or a combination Such a soft rubbery filler and a liquid or gel-like filler are possible. In any case, however, a substantially complete filling of the residual volume of the combustion chamber 5 should be ensured.

If the pyrotechnic drive device 1 is activated from the initial state shown in FIG. 1, the conversion process for the pyrotechnic material 15 is started by means of the ignition device 13. This may be, for example, an electrical ignition device, which can be controlled accordingly via electrical connections 13a. Such ignition devices are known in many forms and therefore need not be described in detail at this point. Instead of electrically controllable ignition devices, of course, other ignition devices can be used, for example, those that can be triggered by vibrations, that is, mechanical accelerations.

By the reaction of the pyrotechnic material 15, the pyrotechnic drive device 1 is converted into the final state shown in Fig. 1 b. In this case, essentially two different mechanisms are to be decided, which lead to the generation of an output power in a central region A with respect to the output shaft area of the diaphragm 17.

On the one hand, a deflagrating pyrotechnic material 15 can be used, which generates a gas pressure in the combustion chamber 5, wherein the pressure increase is slower than the speed of sound in the filler 21. In this case, the membrane is deformed until an initial state corresponding to Fig. 1 b achieved is.

On the other hand, a detonatively converting pyrotechnic material 15 can be used, which first generates a shock wave in the combustion chamber 5, which propagates faster in the filling material 21 than the speed of sound in the filling material 21. This shock wave is first on the membrane 17 and driven by this on the Transmit element 19, which abuts the output region of the diaphragm 17 in the initial state. This leads to the transmission of a high impulse to the driving element 19, which is then thrown with a corresponding kinetic energy from the membrane surface (see Fig. 1 b).

In addition, the detonatively converting pyrotechnic material 15 also leads to a slower pressure increase in the combustion chamber 17, so that in this case, too, a deformation of the membrane takes place. However, this is only effected after the energy of the shock wave, which impinges on the output region of the diaphragm 19, has already been transmitted to the element 19 to be driven.

In order to limit the deformation of the diaphragm 17 in the final state shown in FIG. 1 b, in the embodiment of a pyrotechnic drive device 1 shown in FIG. 1, an annular limiting element 23 is used, which is also held coaxially to the longitudinal axis A in the housing 3. For this purpose, the housing may have on its front side a flange, which surrounds the annular limiting element 23 on its front side radially inwards.

The holder of the bottom element 17 in the housing 3 can be carried out analogously. The housing may for this purpose also have on its rear or bottom side a radially inwardly directed bottom wall. The bottom element 7 is supported in the axial direction with respect to the inside of this bottom wall.

To install the pyrotechnic drive device 1, the bottom element 7 can thus be inserted into the housing with pyrotechnic unit 1 1 already arranged therein, until the bottom element 7 rests against the bottom wall of the housing 3 with its underside or rear side. Subsequently, the filling material 21 can be introduced. Finally, the membrane 17 and the limiting element 23 can be inserted into the cylindrical housing 3, which is initially still open towards the front, wherein the membrane rests with its inside on the filling material. Subsequently, a mechanical beading of the cylindrical housing wall can be carried out such that the Begrenzugselement is held securely in the housing and the membrane is pressed with a predefined force against the filling material 21. In this way, voids in the combustion chamber, which are not filled by the filling material 21, can be avoided. When reacting the pyrotechnic material 15, in addition to generating a gas pressure, which results solely from the conversion process of the pyrotechnic material 15, an additional gas pressure can be generated in that at least a part of the filling material 21 is converted into the gaseous state by the energy released during the conversion process becomes. In this way, the mass of the pyrotechnic material can be reduced compared to a combustion chamber filled only with gas in the initial state. Furthermore, a steeper pressure rise can be achieved thereby, so that the membrane is transferred faster, that is, with greater acceleration from its initial state to the final state. If the element 19 to be driven is to be accelerated substantially exclusively by utilizing the deformation movement of the membrane 17, an additional conversion of the filling material 21 into the gaseous state is thus advantageous. The filling material 21 can be chosen according to this requirement.

For this purpose, in particular liquids, such as synthetic or natural oils, especially vegetable oils in question.

If, on the other hand, the energy of a shock wave is to be transmitted to the element 19 to be driven, the conversion of the filling material 21 into the gaseous state is rather undesirable. Because the energy of the shock wave is transmitted to the driven element 19 at a time, which is before the time of slower deformation of the membrane, which is caused by the generation of hot gases in the combustion chamber 5.

If it is desired to throw away one or more elements 19 to be driven from the output region of the membrane 17, the use of a detonating pyrotechnic material 15 will be used in particular if the one or more elements 19 to be driven have a relatively low mass and as far as possible high speed are to be thrown.

In contrast, one will use a deflagrating pyrotechnic material 15 in such precipitates when the one or more elements to be driven te 19 have a higher mass or should be thrown away from the surface of the membrane 17 at a lower speed.

Furthermore, one will use the last-mentioned movement mechanism above all when the element 19 to be driven is firmly connected to the membrane 17 and serves to act on another element or another device.

The illustrated in Fig. 2 further embodiment of a pyrotechnic drive device 1 differs from the embodiment shown in Fig. 1 only in the features described below, so that the matching with the embodiment in Fig. 1 features need not be described again.

In the embodiment shown in FIG. 2, an adhesive layer 27 is provided instead of a driven element 19 on the membrane 17 in the central output region, which serves for fixing a powdered or dust-like substance 25. In Fig. 2a, only three particles are shown in oversize for symbolizing a powdered or dust-like substance. The adhesive layer may be, for example, an adhesive layer or a dried sugar solution. The powdered or dusty substance 25 may be a drug to be injected into a human or animal tissue.

In such an embodiment, according to the above, primarily a detonatively reacting pyrotechnic material 15 will be used because the powdered or dusty particles of the fabric 25 must be accelerated to as high a speed as possible so that they cover the surface of the fabric The injection should take place, penetrate to a sufficient depth.

2b shows the final state of the pyrotechnic drive device 1 and the powder or dust-like substance particles of the substance 25 already ejected from the surface of the membrane 17. Since parts of the adhesion layer 27 can also detach from the membrane surface, the adhesive layer can be made from such a material or Consist of substance that behaves neutrally when injecting into the tissue or at least does not lead to adverse consequences.

The membrane 17 may, as shown in FIGS. 1 and 2, be formed of multiple layers. In particular, a first and a second layer can be connected to a total membrane 17 via a connecting layer. This drastically reduces the likelihood of rupture of the membrane, as it is highly unlikely that both membrane layers have faulty weak spots at the same location which would result in destruction of the pertinent layer without the provision of a second layer. In addition, additional stability can be achieved by the bonding layer.

The pyrotechnic drive device 1 shown in FIG. 2 additionally has a gas outlet opening 29 in the base element 7, which is closed with a membrane 31 in the initial state (FIG. 2 a). The membrane 31 is designed such that it is destroyed when a limit pressure in the combustion chamber 5 is exceeded.

In the embodiment shown in FIG. 2, since the shock wave generated by the detonating pyrotechnic material 15 is utilized to accelerate the pulp particles 25, rather than the relatively slow deformation of the diaphragm 17 due to the gas pressure generated in the combustion chamber 5 (FIG. relatively slowly), the membrane 17 can be made weaker in this case, if the occurring within the combustion chamber 5 gas pressure is limited to a relatively low maximum value. This is determined by the geometry of the gas outlet opening 29 and the limit pressure at which the membrane 31 is destroyed.

As can be seen from FIGS. 1 and 2, the limiting element 23 has the task of limiting the deformation of the membrane 17 and of supporting the membrane in an annular region which surrounds the output region as soon as the deformation of the membrane 17 has progressed so far. that the respective membrane regions abut the inner wall of the delimiting element 23. The illustrated in Fig. 3 further embodiment of a pyrotechnic drive device 1 largely corresponds to the embodiment shown in Fig. 1. It differs only in that the volume of the combustion chamber 5 is reduced by an annular filling piece 33. The geometry of the filler 33 can be chosen so that the combustion chamber 5 is kept as small as possible. However, the front area of the combustion chamber 5 must be at least in cross section (perpendicular to the longitudinal axis A) such that the cross section is as large as the output region of the membrane, which contributes to the transmission of the energy of the shock wave or by its deformation, the energy transfer to the at least one element 19 to be driven causes.

The filler 33 may, as mentioned above also consist of a material which is fixed in the initial state of the drive device 1 and pass through the increase of pressure and temperature in the combustion chamber after activation of the pyrotechnic material in the liquid or gaseous state. In particular, the filler 33 may also consist of dry ice, which is easy to process and in the final state of the drive means in the (closed) combustion chamber generates a constant pressure with which the membrane 17 is constantly acted upon. In this way, an element connected to the membrane or permanently urged to be driven element can be held in its final position.

It should be noted at this point that a driven element 19, of course, can not only be acted upon by the side of the membrane 17 directed outwards with respect to the combustion chamber, or connected to this side, as shown in FIGS. 1, 3 and 4 is. Rather, the element 19 to be driven can also be acted upon by, or connected to, the inner side of the membrane with respect to the combustion chamber 5. In this case, the driven element 19 extends through the combustion chamber and may protrude with an end portion of the combustion chamber and optionally from the housing 3 of the relevant pyrotechnic drive device 1. In this case, the element 19 to be driven will preferably be connected to the membrane or designed in one piece with it. At the point at which the driven element 19 leaves the combustion chamber and, for example, through a corresponding opening in the bottom part of the bottom part. 7 protrudes, the driven element 19 may be sealed with a sealing means against the interior of the combustion chamber or a through hole in the bottom part 7. However, if a gel-like, pasty or rubbery filling material used in the interior of the combustion chamber 5, it may be dispensed with a seal, if it is acceptable in the relevant application that hot gases from an unsealed outlet opening, for example, a ring surrounding the area to be driven from the Housing 3 or the bottom part 7 exit.

However, the remaining, unsealed outlet opening may only be so large that sufficient pressure can still build up inside the combustion chamber to deform the membrane. The limiting element 23 may be formed in these embodiments so that the entire outer side of the membrane is supported in the final state. Because the limiting element 23 is not penetrated by a driven element in this case.

In this embodiment, the pyrotechnic unit 1 1 can of course not be provided axially in the axis A of the pyrotechnic drive device 1. However, since the position of the pyrotechnic material 15 or the ignition device 13 is not critical, in these embodiments, the pyrotechnic unit 1 1 protrude from one side of the housing 3 ago in the combustion chamber. The pyrotechnic material 15 or the entire pyrotechnic unit 11 must be provided in any case so that it does not interfere with the movement of the driven element 19, which passes through the combustion chamber 5.

The embodiment of a pyrotechnic drive unit 1 shown in FIG. 4 differs from all the previously described embodiments in that, instead of a membrane which transfers the energy to the one or more elements 19 to be driven or the substance particles adhering to a surface, a displaceable piston 35 which limits the combustion chamber 5 (Figure 4a). The housing 3 is in this case formed on its front side so that only a relatively small aperture opening in the longitudinal axis A of the pyrotechnic unit 1 is provided, through which an element to be driven 19th protrudes. The driven element 19 may, as in the case shown, be connected to the piston 35.

Incidentally, the pyrotechnic drive unit shown in Fig. 4 has the same features as the embodiment shown in Fig. 1, particularly as regards the housing, the bottom part and the pyrotechnic unit.

The piston 35 may be fixed in its initial position in the housing 3, for example by latching means, which are provided on the inner wall of the housing 3 and / or the outer wall of the piston 35. This latching means or fixing cause that the piston 35 is accelerated only at a limit pressure is exceeded in the direction of the front of the housing 3.

In this embodiment, it is preferable to use a deflagrating pyrotechnic material 15 because the piston 35 with its inertial mass is hardly movable by a shock wave alone. Rather, for this purpose, the building up in the volume of the combustion gas pressure is needed.

As shown in Fig. 4, the outer periphery of the piston 35 can achieve a sealing effect, that a relatively thin circumferential wall portion of the piston in the radial direction can be acted upon by the building up in the combustion chamber 5 gas pressure. In this way, a radial pressing of the circumferential, relatively thin wall is achieved on the inner wall of the housing 3. This leads to the desired sealing effect when building up the gas pressure in the combustion chamber 5, also during the movement of the piston 35 in the direction of the axis A.

As can be seen from FIG. 4 b, the element 19 to be driven is firmly connected to the piston 35 in the embodiment shown in FIG. 4. The element 19 can thus serve as an output element for acting on a further element or a further device. Of course, however, the driven element 19 may not be connected to the piston 35. In this case, it may already be acted upon by the piston 35 in the initial state. The fixation of the element 19 can be achieved by a corresponding configuration of the opening in the Housing 3 done. However, the element 19 can not be acted upon by the piston 35 in the initial state and can only be fixed in the aperture opening of the housing 3. In this case, the piston 35 first strikes the driven element 19 at a certain speed and transmits a mechanical impulse to the element 19 so that it accelerates in the direction of the axis A and is thrown away.

In the embodiment shown in FIG. 4, in one variant, the element 19 to be driven can pass through the combustion chamber 5. With regard to this variant, reference is made to the above statements.

The embodiment of a pyrotechnic drive device 1 shown in FIG. 5 corresponds to a combination of the embodiments in FIGS. 2 and 3. Here too, a membrane is used in which a powdery or dust-like substance 25 is applied to the outer surface of the output region of the membrane 17 is. An adhesive layer was omitted here to indicate that a pure adhesion may be sufficient to provide the powdered or dust-like substance 25 on the surface of the membrane 17. Of course, however, an adhesive layer such as an oil or a Zückerlösung can be used here as well. Incidentally, the embodiment in Fig. 5 largely corresponds to the embodiment in Fig. 2, but in the combustion chamber, a filling piece 33 is provided according to the embodiment of FIG.

In addition, however, the operation of the embodiment of Fig. 5 differs therefrom from the above embodiments in which a pyrotechnic material 15 to be detonated is used, characterized in that a momentum transfer element 37 is provided in the axis A immediately before the pyrotechnic material 15. This momentum transfer element 37 is in terms of the material and its mass and its geometry such that it is able to be accelerated by the generated pressure surge or the generated pressure wave in an extremely short time to such a speed that the pulse transmission element 37 quasi on the Front of the shock wave rides. This ensures that the pulse transmission element practically together with the foremost Front of the shock wave against the inner wall of the diaphragm 17 is thrown. Thus, not only the energy contained in the shock wave is used to transmit a pulse by means of a very rapid deformation of the diaphragm 17 in the output region, but also the mechanical pulse of the pulse transmission element 37 is used to at least a part thereof on the membrane 17 and to transfer the membrane 17 to the particles of the fabric 25.

The end position of the membrane 17 or of the momentum transfer element 37 is shown in FIG. 5b. In this end position, in turn, the (not to be avoided and not contributing to the acceleration of the material particles) deformation of the membrane 17 can be seen.

In the embodiments according to FIGS. 3 and 5, the filling piece 33 also serves to fix an annular edge region of the membrane 17 by clamping this edge region between the filling piece 33 and the limiting element 23. Of course, however, the membrane 17 may also be connected to the respective edge region with the filling piece 33 or the delimiting element 23.

The filler can also be designed in terms of its geometry that not only a reduction of the combustion chamber volume as far as possible is achieved, but also a focus of the shock wave generated by the pyrotechnic unit 1 1 is achieved on the output region of the membrane. For this purpose, the axial opening of the filling piece 33 could, for example, be designed to widen conically in the direction of the membrane.

Of course, the above-described embodiments can also be modified to further variants by combining certain features of one embodiment, where appropriate, with the features of another embodiment.

All embodiments of the pyrotechnic drive unit can either be integrated into a higher-level device, for example a needleless injection device. Device or an electrical switch or the like, or be designed as an independent unit.

LIST OF REFERENCE NUMBERS

1 pyrotechnic drive device

3 housing

5 combustion chamber

7 floor element

9 receiving recess

11 Pyrotechnic unit

13 ignition device

13a Electrical connections

15 Pyrotechnic material

17 membrane

19 Element to be driven

21 filling material

23 limiting element

25 powder or dust-like substance

27 adhesive layer

29 gas outlet

31 membrane

33 filler

35 pistons

37 pulse transmission element

A longitudinal axis

Claims

claims

1. Pyrotechnic drive device

(a) with a housing (3) in which a combustion chamber (5) with a pyrotechnic material (15) arranged in the combustion chamber (5) and an activation device (13) for activating the pyrotechnic material (15) is provided,

(b) wherein the combustion chamber (5) is delimited by a combustion chamber wall (3, 7, 13, 17, 33, 35) which is closed on all sides, at least in an initial state of the pyrotechnic drive device, which in one or more subregions is in each case provided with an admission surface in each case by an admission element (17, 35) is formed, wherein each loading surface of a biasing member (17, 35) after activating the pyrotechnic material (15) is acted upon by a pressure generated thereby, that the biasing member (17, 35) moves and / or deformed and / or a mechanical impulse is transmitted via the loading element (17, 35) to an element (19) which is mechanically connected thereto at least in the initial state or an associated material (25), characterized

(c) that a residual volume of the combustion chamber (5), in which no pyrotechnic material (15) is provided in the initial state, is substantially completely filled with a liquid, gelatinous or pasty filling material (21) and / or a soft rubbery filling material (21) is.

2. Pyrotechnic drive device according to claim 1, characterized in that the pyrotechnic material (15) is a detonatively implementing material or a deflagrierend implementing material.

3. Pyrotechnic drive device according to claim 1 or 2, characterized in that the soft rubber-like filling material (21) is a silicone-based or rubber-based material, which preferably has a hardness of less than or equal to 70 Shore A.

4. Pyrotechnic drive device according to one of the preceding claims, characterized in that the pyrotechnic material (15) is formed so that a shock wave is generated and that the filling material (21) is such that the shock wave impedance of the filling material (21) substantially the shockwave impedance of the one or more urging elements (17, 35) is equal to or differs only by a predetermined small amount thereof.

5. Pyrotechnic drive device according to one of the preceding claims, characterized in that the filling material (21) has a low shock wave attenuation in order to achieve a low-loss transmission of the energy of the shock wave to the one or more impingement elements (17, 35), which at Activation of the pyrotechnic material (15) are generated.

6. Pyrotechnic drive device according to one of the preceding claims, characterized in that the filling material (21) is a synthetic oil, for example a silicone oil, or natural oil, for example a vegetable oil, in particular sunflower oil, or a silicone oil gel.

7. Pyrotechnic drive device according to one of the preceding claims, characterized in that the filling material (21) or a component thereof has a bumping, wherein the bumping component is preferably water.

8. Pyrotechnic drive device according to one of the preceding claims, characterized in that the biasing element is a movable piston (35) whose travel is preferably limited by in the housing (3) provided stop means.

9. Pyrotechnic drive device according to one of the preceding claims, characterized in that the biasing element is a diaphragm (17) which is held stationary in the housing (3) or which is held in a movable piston, the movement path preferably through in the housing (3) provided stop means is limited.

10. Pyrotechnic drive device according to claim 9, characterized in that

(A) that the diaphragm (17) with an output region, which is preferably a central region of the membrane (17), in the initial state an element to be driven (19), for example a plunger, applied or

(B) that the membrane (17) with an output region, which is preferably a central region of the membrane (17), in the initial state a adhering to the membrane (17) or connected to this to be accelerated and released material (25), for example a pharmaceutical substance, carries.

11. Pyrotechnic drive device according to claim 10, characterized in that the driven element (19) or the substance (25) is arranged completely outside the combustion chamber (5) and that a limiting element (23) is provided, which is an opening for the driven element (19) or for ejecting the material (25) to be detached from the membrane (17) and which limits the deformation path of the membrane (17) in a region outside the output region.

12. Pyrotechnic drive device according to claim 10, characterized in that the driven element (19) passes through the combustion chamber (5) and in the initial state at a position away from the membrane (17) of the combustion chamber (5) from the combustion chamber (5) or the housing (3) of the pyrotechnic drive device (1) protrudes or terminates flush with it, wherein preferably a limiting element (23) is provided which limits the deformation path of the membrane (17), preferably in the entire region of the membrane (17), which undergoes deformation upon activation of the pyrotechnic material (15).

13. Pyrotechnic drive device according to one of claims 9 to 12,

characterized in that the membrane (17) is formed as a multilayer membrane, preferably as a double-walled membrane having a first and second walls, which are connected via an intermediate layer, for example glued.

14. Pyrotechnic drive device according to one of the preceding claims, characterized in that the pyrotechnic material (15) is a detonatively converting material and that the housing (3) of the combustion chamber (5) or at least a part of the combustion chamber wall of a good heat-conducting material, such as a good heat-conducting metal such as copper or aluminum, or that at least part of the combustion chamber wall is formed by a filler (33), which consists of a solid in the initial state of the pyrotechnic drive means material which liquefies after activation of the pyrotechnic material (15) at least partially or is converted into the gaseous state.

15. Pyrotechnic drive device according to one of the preceding claims, characterized in that it is a functional unit for installation or interchangeable insertion into a higher-level device, such as a pyrotechnic electric switch or a pyrotechnic needleless injection device for needle-less injecting a dust or powdered substance in a tissue of a body, is formed. Pyrotechnic drive device according to claim 9, characterized in that the membrane (17) has a the output range or provided within the output range, with respect to the combustion chamber (5) inwardly directed preforming, which is designed for shock wave steering and / or for generating a cracking ,